Skip to content
Home
About
Meet the Team
Join the team
Alumni
The Principal Investigator
Forschen in Singapur?
Research
Publications
Teaching
CM4212 – Main Group
CM4212 – TM OM
CM1111
Blog
Search for:
Home
About
Meet the Team
Join the team
Alumni
The Principal Investigator
Forschen in Singapur?
Research
Publications
Teaching
CM4212 – Main Group
CM4212 – TM OM
CM1111
Blog
Search for:
Carbonyls
1. Reduction of a metal-carbonyl complex generally leads to...
increase of M–C distance.
decrease of M–C distance.
increase of C–O distance.
decrease of C–O distance.
Show answer
Backdonation from metal to carbonyl strengthens the metal-carbon bond, but weakens the carbon-oxygen bond.
2. Carbonyl complexes are favorably formed with low valent metal centers.
False
True
Show answer
Carbonyl ligands are good pi-acceptors. Low valent metal centers provide sufficient electron density for favorable pi-backbonding to bound carbonyl ligands.
3. Coordination of a carbonyl ligand to a low valent metal generally leads to...
shortening of the C-O bond.
lengthening of the C-O bond.
no change of the C-O bond.
Show answer
Carbonyl is a very good pi-acceptor ligand. Coordination to a low valent (i.e. electron-rich) metal center will lead to backdonation into the antibonding pi* orbital, thus weakening the carbon-oxygen bond.
4. The number of carbonyl bands in the IR spectrum is indicative of the number of CO ligands in the complex.
True
False
Show answer
This is not the case. A octahedral, homoleptic hexacarbonyl complex of the type [M(CO)6] exhibits only one band.
5. What does the Tolman Electronic Parameter measure?
It measures the amount of sigma donation of phosphines in [Ni(CO)3L] complexes.
It measures the amount of backdonation to phosphines in [Ni(CO)3L] complexes.
It measures the amount of sigma donation of CO ligands in [Ni(CO)3L] complexes.
It measures the amount of backdonation to CO in [Ni(CO)3L] complexes.
Show answer
The TEP is the A1 carbonyl stretch in complexes of the type [Ni(CO)3L]. It is therefore directly linked to the amount of backdonation to the carbonyl ligands.
6. Nucleophilic attack of a bound carbonyl occurs at...
the oxygen atom.
the CO triple bond.
the carbon atom.
Show answer
Upon donation of the lone pair to the metal, there will be partial positive charge at the carbon atom, which makes it prone to attack by nucleophiles.
7. Homoleptic carbonyl complexes exhibit only one CO band.
False
True
Show answer
The number of carbonyl bands depends on the number of unique carbonyl ligands, which in turn is influenced by geometry and symmetry.
Page 1 out of 3
